Information technology including personal computers has been rapidly advancing in recent years, and similar progress has been made in peripherals attached to personal computers. In particular, the capacity of magnetic recording apparatus for storing data is increasing year by year, and thus high density recording is in demand for magnetic recording disks for storing information. Accordingly, an area recording density of 20 GB/cm2 or higher is required on magnetic recording disks. This means that adjacent pieces of recorded information need to be aligned at a pitch of 1 μm.
A magnetic head is used for writing data to or reading data from the magnetic recording disk. This magnetic head is supported by a head supporting mechanism. The magnetic head is moved to the desired position by scanning this head supporting mechanism over the plane of the magnetic recording disk. Accordingly, the magnetic head needs to be positioned to a high degree of precision for writing or reading high-density information.
In addition to increased capacity, high-speed information reading and writing are needed in magnetic recording apparatus. This requires the magnetic recording disk to be rotated at high speed and the magnetic head to be positioned at high speed.
However, high-precision positioning of a magnetic head is difficult to control when it is scanned at high speed by means of a conventional head supporting mechanism. On the other hand, the magnetic head is difficult to move at a high speed when it is highly accurately controlled. In other words, it is becoming difficult to satisfy the requirement that a magnetic recording unit be able to record a large volume of data at high speed on a disk.
The reason for the difficulties in achieving high-speed transfer and high-precision control of the magnetic head are briefly described next. In the latest large-capacity magnetic recording apparatus, the magnetic recording disk is rotated at high speed and the magnetic head moves horizontally to the magnetic recording disk to a position where information is recorded (or to be recorded) by the supporting mechanism of the magnetic head. However, the high-speed horizontal movement generates a large inertial force on the magnetic head attached to the tip of the head supporting mechanism, making it difficult to halt it precisely at the predetermined position.
One proposed method for correcting this positional deviation of the magnetic head caused by the inertial force is a micro-transfer device which uses a piezoelectric element at the tip of the head supporting mechanism. An electrode for changing the shape of the piezoelectric element is formed directly on the piezoelectric element, and the shape of the piezoelectric element naturally changes when voltage is supplied to the piezoelectric element. This means the shape of the voltage feeder also changes, making the voltage supply unstable.